* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Outfit', sans-serif;
    background: #0f172a;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: #f8fafc;
}

.calculator-container {
    width: 100%;
    max-width: 400px;
    padding: 20px;
}

.calculator-card {
    background: #1e293b;
    border-radius: 24px;
    padding: 30px;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.2);
    border: 1px solid #334155;
}

.header {
    margin-bottom: 25px;
    text-align: center;
}

.header h1 {
    font-size: 32px;
    background: linear-gradient(135deg, #38bdf8, #818cf8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 700;
}

.header p {
    color: #94a3b8;
    font-size: 14px;
    margin-top: 5px;
}

.display-section {
    background: #0f172a;
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 20px;
    border: 1px solid #334155;
    position: relative;
    overflow: hidden;
}

.display-section::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 4px; height: 100%;
    background: linear-gradient(to bottom, #38bdf8, #818cf8);
}

.result-box {
    text-align: right;
    font-size: 36px;
    font-weight: 600;
    color: #f8fafc;
    word-break: break-all;
}

.inputs-section {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
}

input {
    flex: 1;
    width: 100%;
    background: #0f172a;
    border: 1px solid #334155;
    border-radius: 12px;
    padding: 15px;
    color: #f8fafc;
    font-size: 16px;
    font-family: inherit;
    transition: all 0.3s;
}

input:focus {
    outline: none;
    border-color: #38bdf8;
    box-shadow: 0 0 0 2px rgba(56, 189, 248, 0.2);
}

.operations-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
}

button {
    font-family: inherit;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 15px;
    border-radius: 12px;
    border: none;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    transition: all 0.2s;
}

.op-btn {
    background: #334155;
    color: #f8fafc;
}

.op-btn:hover {
    background: #475569;
}

.op-btn:active {
    transform: scale(0.98);
}

.clear-btn {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.clear-btn:hover {
    background: rgba(239, 68, 68, 0.2);
}

.error-msg {
    color: #ef4444;
    font-size: 14px;
    margin-top: 15px;
    text-align: center;
}

.hidden {
    display: none;
}